Luminous dial



NOV. 17, 1936. R G FORDYCE 2,061,097

LUMINOUS DIAL Filed June 2, 1935 2 Sheets-Sheet l INVENTOR ATTORNEY Nov.17, 1936. R. G. FRDYCE LUMINOUS DIAL Filed June 2, 1935 2 Sheets-Sme?I 2A INVENTOR @y/@ I,TToRNEY Patented Nov. 17, 1.936

UNITED STATES PATENT OFFICE Radium Dial Company, New York, N. Y., acorporation of Delaware Application June 2, 1933, Serial No. 673,992

11 Claims. (Cl. 40-10.5)

This invention relates to self-luminous devices and with particularltyto methods and means for increasing the apparent optical delineation ofself-luminous indicia or markings.

In various arts it is highly desirable to provide devices or mechanismswith indicia or markings which are self-luminous, and in many cases themarkings must be capable of accurate visibility in subdued lightorintotal darkness. For example, in the automatic telephone art, whichemploys selectively operable dials or the like, the subscriber orcalling party is very frequently required to manipulate the dial indarkened rooms, booths, etc. It has been suggested heretofore to employon the dial self-luminous indicia or characters. When it is consideredthat the eiliciency of a telephone plant is a function of the variousholding times of the various trunks, selectors, etc., used inconjunction with the dial, it is of the utmost importance that anyindicia employed must be of the highest degree of visible delineation,otherwise the calling party will from time to time mistake one indiciafor another, with the resultant false operation of the automaticselective mechanism. Ordinary indicia of self-luminous materials havenot been adopted for universal use in automatic dial systems, probablybecause the apparent visible delineation of the self -luminous indiciaor characters is insuiilcient. It Ais a. well-known fact that if acharacter is painted, printed, embossed or `otherwise formed fromordinary self-luminous materials, the delineation or outline of thecharacter is' very difficult to determine. This may be due in part tothe fact that with ordinary methods of forming the self-luminousindicia, the edges or outlines are not specially delineated with therequired accuracy. However, it is also an inherent characteristic ofself-luminous materials themselves that they exhibit a fuzziness orblurred characteristic at the edges. This is all the more pronouncedbecause the visible luminosity of selfluminous or phosphorescentmaterials is extremely low. As a result of this inherent limitationcertain indicia or characters are in many cases indistinguishable fromone another. For example the numeral 6 is very often mistaken for thenumeral 8 and vice versa; the numerals 3 and 8 are likewise difficult todistinguish. It is obvious, therefore, that the use of ordinaryselfluminousv indicia on a telephone dial or the like, may be the causeof numerous wrong connections, resulting from the fact that the callingparty is unable readily to distinguish one numeralor letter fromanother.

lent in other arts where self-luminous indicia are employed.

Accordingly, it is a principal object of this in- The disadvantages setforth above'in connection with automatic telephone dials are also, to agreater or less degree, prevavention to provide a method and means forincreasing the apparent sharpness of delineation of self-luminousindicia or markings on dials or other similar devices. 4

A feature of the invention relates to the combination of a carrierhaving thereon a series of self-luminous markings ,such as indicia. orthe like, and optical means for enhancing the apparent delineation ofsuch indicia when viewed 1 in a subdued light or in total darkness.

Another feature of the invention relates to a dial or similar devicewhich is provided with selfluminous characters or indicia arranged ingroups, in conjunction with an optical system for each group, wherebythe apparent delineation of the 15 characters in each group ismaterially enhanced.

vA further feature relates to an attachment for automatic telephones orthe like comprising in combination a carrier of self-luminous indicia,

and a lens carrier having a plurality of similar 2o short-focus lenses,one for each group of indicia. A further feature relates to a dialcarrying a series of self-luminous indicia arranged in groups,

in conjunction with a series of lenses, one for .and proportioning ofparts whereby a cheap dial attachment for automatic telephones or thelike is provided having a maximum of visibility in'` subdued light.

Other features and advantages not specifically enumerated will beapparent after a consideration ofthe following detailed description andthe appended claims.

i While the invention will be disclosed herein as embodied in a dial forautomatic telephone systems and the like, it will be understood thatthis is done merely for the purposes of illustration and explanation andnot by way of limitation, the inventive concept being capable ofembodiment in' any situation requiring self-luminous marking havingmaximum visual delineation.

Accordingly, in the drawings, Fig. 1 is a top plan view of the membercarrying the self-luminous markings; v

Fig. 2 is a plan view of a rotatable member that may be used inconjunction with the member of Fig. 1;

Fig. 3 is a top plan view of a lens carrier to be used in conjunctionwith the member of Fig. 1;

Fig. 4 is anelevational view partly in section, so

showing more clearly the relation between the movable dial and the fixeddial;

Fig. 5 is a top plan view of Fig. 4;A

Fig. 6 .shows a preferred modification of the embodiment of Fig. 4;

Fig. 7 shows a still further modification of the embodiment of Fig. 4;and

Fig. 8 is a detail sectional view of one manner of fastening the lensesin position.

Referring more particularly to Figs. 1 to 4, the numeral I represents arotatable dial such as is ordinarily employed in automatic telephonesystems and comprises a series of ilnger holes 2 to II inclusive. Theconstruction of this dial forms no part of the invention and it suillcesfor the present, the dial is provided with the usual mechanism wherebyduring rotation it controls the operation of the usual automaticselective switch mechanism. In accordance with standard practice, eachof the holes 2 to II is associated with a group of letters or numerals.

Adapted to surround the dial I is an annular- Shaped channel member(Fig. 4), of metal, bre, or other suitable material preferably, althoughnot necessarily having its inner surface blackened o r otherwiserendered non-reflecting. Fastened to the bottom of the channel memberlI2 is an annular strip I3 which rserves as the carrier for theself-luminous markings or indicia. I4. As shown more clearly in Fig. 1,the self-luminous markings are arranged in groups, there being a groupassociated with each of the finger holes 2 to II inclusive. The memberI2 is so mounted with relation to the member I that when the lattermember is in its normal position, the finger hole 3 will be in radialalignment with the characters A-B-C-2, the hole l will be in radialalignment with the characters D-E-F-3, and so on, with the remaininggroups of characters. Attached to the top of the member I2 is anotherannular member I5 of metal, fibre, or suitable material. The member I5is provided with a seties of openings in which are positioned lenses I6to 25 inclusive. 'I'he member I5 is positioned so that the lens I1 isdirectly above and in optical alignment with the characters A-B-C-il;

the lens I8 is directly above and in optical allgnment with thecharacters D-E-F--3, and so on for the remaining lenses. Any convenientmeans may be employed for fastening the lens carrier I5 to the memberI2, and similarly, any convenient means may be employed for fasteningthe individualy lenses in place in the carrier I5. For example, themember I5 may consist of two separate annular plates having alignedopenings to receive the lenses, with the edges of-each lens clampedbetween the opposite sides of the plates. On the other hand, the carrierI5 may have its l outer and inner circular edges threaded as indicatedby the numerals 26, 21 (Fig. 8), and the walls of the member I2 maylikewise be threaded so as to enable the lens carrier I5 to be screwed iinto position. Likewise, if desired, the lenses may be mounted inindividual circular carriers which may be individually and removablyfastened in the member I5.

As set forth above, the characters Il are formed of self-luminousmaterials such as a paint containing phosphorescent materials,radium-lumilines, and If the characters in each group are relativelyclosely spaced, they tend to coalesce visually, thus further reducingtheir visual delineation. On the other hand, with the employment oflenses I6 of a short focal length, when each group of self-luminousindicia is viewed through its associated lens, the visibility anddelineation of each individual character are materially enhanced, asindicated inFig. 5 of the drawings. While the explanation of thisphenomena is not clearly understood, it may be due to the fact that thelenses have a resolving power which enables the body of self-luminousmaterial in each character to be accurately imaged without imaging theirregular self-luminous particles around the edge of each character. Inany event, numerous experiments prove that the use of selfluminouscharacters in conjunction with short focal lenses enables the charactersto be positioned in closer array without rendering them blurred or vagueto the eye when viewed through the lenses. Quite apart, therefore, fromthe increased visibility or delineation of each character there isrendered possible a saving in luminescent material, since theself-luminous characters may be grouped closer together and may be ofmuch characters. In other words, each lens is designed as to focallength and aperture, so that the apparent delineation of the individualcharacters in each group is materially increased.

Instead of mounting the designation strip I3 in a plane parallel to thedial I as in Figs. 1l to 5, this designation strip may be mounted at anangle to the dial so as to enable all the indicia to be viewablesimultaneously through the respective lenses, from a common point. Thus,as indicated in Fig. 6, the strip I3 carrying the selfluminous indiciaIl is attached to the annular channel member I2 at a slight angle.Similarly, the individual lenses I6, I1, etc., are mounted substantiallyparallel to the strip I3 so that an observers eye at the point P, forexample, is capable of viewing all the indicia I 4 simultaneouslythrough the respective lenses. While Fig.

v6 shows one specific manner of mounting the designation strip and thelenses at an angle to .the axis of the dial, it will be understood thatthis is merely illustrative, and that any other well-known manner ofpositioning these parts in desired relation as set forth may beemployed.

Instead of viewing the indicia directly through the associated lenses,it may be desirable to interpose a reflector or mirror between theindicia and the lenses. Thus, as shown in Fig; '7, the annular channelmember I2 carrying the individual lenses I6, II, etc., is provided witha reiiecting plate 28, which is preferably of a polished metal or thelike, although, if desired, a glass mirror may be employed. Thedesignation strip 29 carrying the indicia instead of being in the formof a nat annular disc as in Figs. 1 to 5, is in the form of a cylinderattached to the inner wall of the annular member I2. Thus the indicia onthe member 29 are in planes at right angles to the the indicia and thelenses is effectively increased.

It will be understood, of course, that the lenses in the embodiment ofFig. 7 may be mounted parallel to the reector 28, as described above inyconnection with Fig. `6, so as to enable the reiiected indicia to beviewed simultaneously from f a common point.

While various specic arrangements and ma-l terials have been mentionedhereinabove, it will vbe understood that the invention is not limitedthereto. For example, the term self-luminous as employed herein, isintended to cover any I mixture containing a phosphorescent, a radiumluminescent compound, or similar materials. Similarly, while a singlelens is shown associated with each group of indicia, this is merelyillustrativeand, if desired, a combination of lenses may be employed. Itwill be also understood that the various groups of indicia, instead ofbeing mounted on a single plate or strip I3, may be mounted onindividual strips so as to be replaceable from time to time. If desired,a protective covering in the form oi an annular strip of celluloid orother transparent material may be positioned over the lenses to protectthem from scratching, breaking, etc.

Various other changes may be made without departing from the spirit andscope of the invention.

What is claimed is:

1. In a device of the character described, a rotatable dial, a carriersurrounding said dial having thereon a plurality of self-luminousindicia, a plurality of short focus lenses, and annular means formounting each lens a predetermined fixed distance from a correspondingarea of said carrier for resolving the light from the indicia to enhancethe visual delineation thereof.

2. In a device of the character described,

means defining an annular channel, a strip carrying radium-luminousmaterial positioned within said channel, lclosure means for said channeland a plurality of spaced 'short-focus lenses mounted in said closuremeans in predetermined spaced relation to said strip.

3. In a device of the character described, the combination of an annularchannel member, another member carrying a series of self-luminousindicia, said other member being mounted within said channel member atan inclined angle, to the axis of said annular member, a. plurality oflenses, and means for mounting said lenses in optical alignment withsaid indicia.

4. In combination, a rotatable member, a xed member surrounding saidrotatable member. a strip carried by said fixed member at an inclinedangle to the rotational axis of said rotatable member, indicia on saidstrip, and a plurality of lenses mounted each in optical alignment withassociated indicia, whereby all said indicia may be simultaneouslyviewed from a common point through said lenses.

`5. In-combination, a rotatable selective device having a plurality ofselecting members positioned therearound, a xed designation dialsurrounding said member and having a plurality of groups ofself-luminous indicia, eachy group being in alignment with acorresponding one of said members,

said indicia being mounted in a plane at an inclined angle to the planeofv rotation of said dial, a plurality of short-focus resolving lenseseach in optical alignment with one of said groups of indicia, andreecting means between the indicia and lenses to enable the reflectedAindicia to ybe viewed through the lenses.

6. In a device of the character described, the combination of an annularchannel shaped member, self-luminous indicia arranged in spaced groupson `the interior of said member, closure means for said channel shapedmember having a plurality of spaced openings therein, a shortfocus lensmounted in each opening in optical alignment with a corresponding groupof indicia, said lenses and closure member cooperating with said channelmember to substantially completely enclose said indicia.

7. In combination an automatic telephone dial, a member surrounding saiddial said member carrying a'plurality of self-luminousindicia arrangedin radial groups, a plurality of short focus lenses, means for mountingeach lens a predetermined iixed distance from a corresponding one ofsaid groups and in optical alignment therewith, and light reecting meansbetween said indicia and said lenses for reecting the light from eachgroup through the corresponding one of said lenses, said reflectingmeans being mounted at an inclination to the axis of rotation of saiddial.

8. In combination a rotatable dial, a strip carrying la plurality ofself-luminous indicia arranged in spaced groups, a plurality of shortfocus lenses, means i'or mounting said lenses at an inclination to theaxis of rotation of said dial so that all said indicia may be equallyviewed' through the lensesl from a single point, the distance of saidlenses yfrom said indicia and the focal length and aperture of thelenses being so proportioned as to increase the apparent delineation ofsaid indicia.

9. In combination, a selective rotatable dial, a designation membersurrounding said dial and iixedly mounted with relation thereto, aplurality of spaced groups of self-luminous indicia on said member, aplurality of short-focus lenses, and common means on said member forxedly mounting each lens in alinement with a corresponding one of saidgroups and at a predetermined distance therefrom, said meanssubstantially completely enclosing said indicia.

10. In combination, a carrier bearing thereon in localized areasself-luminous indicia, a plurality of short-focus lenses, one associatedwith each area for increasing the apparent delineation oi.' saidindicia, means for mounting said lenses 'a predetermined iixed distancefrom each of said areas, and meansy extending upwardly of said carrierfor supporting said lens mounting means.

11. In combination, an annular carrier bearing thereon in localizedareas radium-luminous indicia, a light-collecting and resolving memberassociated with each area for enhancing the discernibility of saidindicia, and annular support means for supporting said members apredetermined fixed distance from their associated areas.

RUFUS G. FORDYCE.

